Diaphragm horn



J s. G. DOWN 2,142,184

DIAPHRAGM HORN Filed Jan. 18, 1936 v INVENTOR 200 50 I BY ATTORNEY SIDNEY GDUWN Patented Jan. 3, 1939 UNITED STATES PATENT OFFICE DIAPHRAGM HORN Application January 18, 1936, Serial No. 59,706

2 Claims.

This invention relates to a sound producing device'and more particularly to a device of the type employing a vibratory diaphragm.

It isthe principal object of this invention to 5 provide an improved sound producing device of the type referred to and which is operated by fluid under pressure.

Afurther object of the invention is to provide a 'sound producing device of the type referred to which incorporates means to adjustably vary the tone of the sound produced by the device.

4 Another object of the invention is to provide an improved sound producing device which is simple and rugged in construction-and efiilcient in operation.

Other objects of the invention and features of novelty will be apparent from the following description taken in connection with the accompanying drawing in which Fig. 1 is a fragmentary sectional view of a sound producing device embodying my invention,

Fig. 2 is an elevational view of the diaphragm employed in the device shown in Fig. 1,

Fig. 3 is a fragmentary sectional view taken substantially along the line 3--3 of Fig. 1, and

Y Fig. 4 is a sectional view of a portion of a sound producing device showing a modified form of construction which I may employ.

' Referring to Fig. 1 of the drawing, the sound producing device therein illustrated comprises a drical portion 5 of the casing section I.

casing section I, a casing section 2, and a flexible diaphragm 3.

The casing section I comprises a substantially *j cylindrical portion 5 of relatively large diameter 5 which is connected to a horn bell portion 6 through a portion of relatively small diameter indicated at 8. The casing section I has formed integral therewith inwardly extending prongs H) which terminate in enlarged heads I 2 having sub- 40 stantially flat faces which are adapted to engage tially of the diaphragm.

The prongs l0 and the recesses-in the margin of the diaphragm 3 are arranged so that when the diaphragm is in position in the cylindrical portion 5 of the casing section I, the heads l2 of the prongs I 0 engage the face of the diaphragm at points located radially inwardly of the recesses in the margin of the diaphragm.

The casing section I has threads 20 cut in the inner face of the cylindrical portion 5, and it has a slot 22 cut therein, while there are ears 24 and 26 formed on the outer face of the casing section on opposite sides of the slot 22. The ear 24 has an opening therein through which extends a screw 28 which extends into a threaded opening in the ear 26. i

Th casing section 2 comprises a substantially cylindrical member having threads cut in the periphery thereof which are adapted to cooperate with the threads 20 cut in the inner face of the cylindrical portion 5 of the casing section I. 5

The casing section 2 has formed thereon a substantially annular seat rib 30 which projects from the face of the casing section 2 and is adapted to engage a face of the diaphragm 3 adjacent th center thereof.

The casing section 2 has secured in an opening therein a pipe 32 which leads from a suitable source of fluid under pressure, not shown, and which is connected through a choke or restricted portion 34 with the chamber 36 within the seat rib 30.

The casing section 2 is screwed into the threaded portion on the cylindrical portion 5 of the casing section I so that the seat rib 30 presses against one face of the diaphragm 3 and thereby presses the other face of the diaphragm against the headsl2 carried by the prongs l0, and so that the diaphragm 3 is deflected slightly, as is clearly shown in Fig. 1 of the drawing.

When the casing section 2 has been turned to the position to give the desired deflection of the diaphragm 3 it may be locked in this position by tightening the screw 28, which contracts the cylindrical portion 5 of the casing section I about the casing section 2 and thus rigidly clamps it 1 position. 40

When it is desired to operate the signal device, fluid under pressure is supplied to the pipe 32 by means, not shown, and it flows therefrom through the choke 34 to the chamber 36 within the seat rib an. Fluid which is supplied to the 45 chamber 36 is confined to this chamber at this time as the diaphragm 3 is firmly pressed against the seat rib 38, thereby cutting off communication between the chamber 36 and the area indicate at 38 outwardly of the seat rib 30. 0

On an increase in the pressure of the fluid in the chamber 36 to a predetermined value, the force exerted by this fluid on the diaphragm 3 is sufiicient to overcome the force resulting from the inherent resiliency of the material of which the diaphragm is constructed and tending to hold the diaphragm against the seat rib 30.

When the pressure of the fluid in the chamber 36 builds up to this value, the diaphragm 3 is forced away from the seat rib 30, thereby permitting the fluid under pressure within the chamber 36 to escape past the seat rib 30 to the area 38 outwardly of the seat rib. When the diaphragm 3 is moved away from the seat rib 30, the flow capacity of the passage opened thereby is substantially greater than the flow capacity of the choke 34 through which fluid under pressure is supplied from the pipe 32 to the chamber 36. Fluid under pressure, therefore, can escape from the chamber 36 at a more rapid rate than the rate at which fluid is supplied thereto, and, as a result, there is a rapid reduction in the pressure of the fluid in the chamber 36.

On this reduction in the pressure of the fluid in the chamber 36, the force exerted on the diaphraghm 3 tending to hold it away from the seat rib 36 is correspondingly reduced, and the diaphragm 3 is returned, by the inherent resiliency of the material of which it is constructed, to a position in which it is in engagement with the seat rib 3D. This cuts oil the release of fluid under pressure from the chamber 36 within the seat rib, and as fluid under pressure is continuously supplied to the chamber 36 from the pipe 32 through the choke 34, the pressure of the fluid in this chamber builds up, and, because of the relatively small volume of the chamber 36, the pressure in this chamber very quickly increases to a value such that the force exerted by the fluid on the diaphragm 3 again exceeds the force tending to press the diaphragm 3 against the seat rib 33. again moved away from the seat rib 30 so as .to again permit fluid under pressure to escape from the chamber 36 at a rate more rapid than the rate at which fluid is supplied thereto through the choke 34. The diaphragm 3 will thereupon again be returned into engagement with the seat rib 33 to cut off the release of fluid under pressure from the chamber 36 within the seat rib 30.

This process will continue as long as fluid under pressure is supplied to the device by way of the pipe 32, and the rapid vibrations of the diaphragm 3 results in the production of vibrations in the air column within the horn bell 6 which causes the device to emit an audible sound.

The fluid under pressure which escapes from the chamber 36 past the seat rib 39 to the area 38 outwardly of the seat rib 30 flows therefrom through the recesses cut in the margin of the diaphragm 3 to the opposite side of the dia- I phragm, and thence to the atmosphere through the horn bell 6.

This sound producing device incorporates means by which the tone of the sound produced by the device may be adjustably varied if desired. This is accomplished by loosening the screw 28 and then turning the casing section 2, which is threaded in the cylindrical portion 5 of the casing section I. This causes the seat rib 39 carried by the casing section 2 to move relative to the heads [2 carried by the prongs l0 and this changes the degree of deflection of the diaphragm 3. This varies the force tending to press the diaphragm 3 against the seat rib 33 as the result of the inherent resiliency of the material of which the diaphragm is constructed, and this varies the pressure to which the fluid in the chamber 36 within the seat rib 30 must build up before the The diaphragm 3, therefore, is.

force exerted by this fluid on the diaphragm 3 is suflicient to move the central portion of the diaphragm away from the seat rib 3. This results in a different rate of vibration of the diaphragm 3 and produces a change in the rate of vibration of the air column within the horn bell 6 which determines the tone of the sound produced by the device.

After the casing section 2 has been turned to the desired position it may be locked in this position byagain tightening the screw 28 which contracts the cylindrical portion 5 of the casing section i about the casing section 2 and holds it in the adjusted position.

In Fig. 4 of the drawing I have illustrated a modified form of construction which I may employ. In the construction shown in this figure a casing section la, which is generally similar to the casing section I employed in the device shown in Fig. l is provided, and has a substantially cylindrical portion 5a which is joined to the horn bell section Ba by a portion of reduced diameter indicated at 8a.

This casing section has formed integral therewith inwardly extending prongs Ina within the cylindrical portion 5a and the ends of these prongs are joined by an annular portion, indicated at i2a, which is adapted to be engaged by a face of the diaphragm 3 at points on the diaphragm radially inwardly of the recesses which are cut in the margin of the diaphragm.

With this form of construction a casing section similar to that indicated by the reference numeral 2, and employed in the device shown in Fig. i is employed, and when it is screwed into the threads 23a on the interior of the cylindrical portion 5a, the seat rib 30 carried thereby presses against the diaphragm 3 forcing the diaphragm against the annular portion I21: and deflecting the central portion of the diaphragm.

The operation of this embodiment of the invention is similar to that shown in Fig. 1, and the fluid under pressure which escapes past the seat rib so on the casing section 2 flows around the diaphragm 3 and through a passage positioned outwardly of the annular portion 121:, and flows between the prongs Ilia to the chamber on the face of the diaphragm, and thence to the horn bell portion 6a from which it escapes to the atmosphere.

It will be seen that this invention provides a sound producing device employing a vibratory diaphragm and incorporating means to adjustably vary the tone of the sound produced by the device. It will be seen also that this device is simple and rugged in construction and is emcient in operation.

While two embodiments of the improved sound producing device provided by this invention have been illustrated and described in detail, it should be understood that the invention is not limited to these details of construction and that numerous changes and modifications may be made without departing from the scope of the following claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a sound producing device, in combination, a member having a seat rib associated therewith, a member having a substantially annular portion adapted to engage a face of a diaphragm, said annular portion being of substantially larger diameter than the seat rib, a flexible diaphragm having one face engaged only by the seat rib and having its otherface engaged only by said annular portion, means for supplying fluid under pressure at a restricted rate to the area within the seat rib, and a communication extending around the periphery of the said diaphragm and located outwardly of said annular portion through which fluid may flow from the area outwardly of the seat rib at one face of the diaphragm to the other face of the diaphragm.

2. In a sound producing device, in combination, a flexible diaphragm, a casing section having a seat rib associated therewith and engaging a face of the diaphragm substantially centrally under pressure at a restricted rate to the area 10 within said seat rib.

SIDNEY G. DOWN. 

